Sectional boiler



4 Sheets-Sheei 1L (No Model.)

J. H. MILLS. SEGTIONAL BOILBR.

Patented Mar. 3l

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(No Model.)

4 Sheets-Sheet 2.

J. H. MILLS. SBGTIONAL BOILBR.

Patented Mar. 31, 1891.

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4 Sheets-Sheet 3.

(No Model.)

J. H. MILLS. SBGTImLM.4 BOILER.

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(No Model.) 4 Sheets-Sheet J. H. MILLS.

SBGTIONAL BOILER.

Patented Mar. 31,1891.

l UNiTnD STATES PATENT Tirion.'Y

.lOl-IN l'fl. MLLS, OF BOSTON, MASSACHUSETTS.

SECTIONAL BOILER.

SPECIFICATION forming part of Letters Patent No. 449,3? 9, dated March31, 18911.

Application tiled November 15, 1890. Serial No. 371,609. (No model.)

To a/ZZ when?, it may concern:

Be it known that l, JOHN H. MILLS, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented new and useful Improvements in Sectional Boilers,of whichthe 'following is a specification.

This invention relates to sectional boile1s,` the object being toprovide for steam and especially for hot-water-heating` apparatus andanalogous uses an improved boiler consisting of cast-iron hollowsections of peculiar construct-ion and arrangement composing` theindividual units of `such boiler, whereby increased heating-surface. isobtained without increasing the cost,A of manufacture, all as`hereinafter fully set forth.l

lathe drawings forming part of this specification, Figure l is a frontelevation, partly in section, of a boiler embodying inyiinprove ments.Fig. 2 is a side elevation, part-ly in section. Fig. 3 is a sectionalView about on line 3 3 of this figure. Fig'. 4 is a rear viewof asection located at the rear end of the gratebars, as belowtdeserib'ed.Fig. 5 is a perspective view of one of the main sections of the boiler,the outflow and return drums with which all of the sections of theboiler coinrnunicate, and a pipe connection between said drums, thepurpose of which is fully described below.

One essential object of this invention is to secure increasedet'iiciency and power to absorb heat for a liquid circulation by placinga part of the heating-surface below the grateline, which surface will beacted upon by the radiant heat of the coals on the grate and the hightemperature of the ash-pit, but which heat is entirely lost in boilershavin g no heat* absorbing' surface below said grate line. lVhile somewroughtiroii or shell boilers have an extension of theirwater-spacesbelow the grate-line and tothe door, they de not and cannotalso extend their smoke-dues to render available the surface soobtained.

lleretofore in the construction of eastnnetal boilers composed ofseparate sections they have been formed of certain tubes and finesdesigned to stand upon foundationfwalls of brick or iron, such wallsforming the ash-pit of the completed boiler.

lVhile the sectional boiler just referred to erate steam as the heatingagent, but to raise the temperature of the water siniplyand circulate itin pipesor radiators located in the rooms and spaces to be warmed. Thereis another and important advantage secu red when using this boiler forcirculating wa` ter instead of steam as a lient medium. This is theincreased height of the columns of water acted upon by the heatduie tothe longer section obtained when starting from the floor and the factthat this pipe conveying the return circulation may enter the boileralso on the floor-level' and without rising' up and forming' a loopinthe return-pipe1 which is a loss of power and efficiency proportioned tothe distance which such return- .pipe rises before entering' the boiler.

I-Ieretofore in the construction of sectional boilers, whether composedof whole sections spanning the grate and [ire-chamber from side to side,or as divided sections covering One-half of the `crate, the sections arecon strueted to be elevated and stand upon a brick or iron foundation,which also forms the ash-pit walls of the completed boiler. [n mypresent invention, however, I dispense with all brick and ironfoundations by constructing my boiler-sections to standdirectly on thefloor, the lower part of such sections Y below the grate-line formingtheir own. fou ndation, and thus avoiding` the expense of brick or ironash-pit walls and the labor of elevating` the heavy castings onto thefoundationgenerally half a yard above the lfloor. This method ofconstructing` cast sectional boilers notonly dispenses with said commonbut useless .foundations as to heat effect upon the water in the boiler,but by formino: the same from the sections themselves increasedheating-surface is obtained in the pipes and tubes extending below thegrate and forming' the walls of the smoke-titles before described.

In the drawings, A indicates the main integral sections of the boiler,each et which is of cast-iron and hollow, and consists of (see Fig. 5)two substantially parallel vertical tubes 4f 4, united by a hollow base5 at their lower ends, and having,` extending therebe` IOO tween atintervals and communicating with the interiors thereof several (threebeing the preferred number) cross or horizontal ducts (i, 7, and S. Thesaid vertical tube 3 of the boiler-section A terminates at andcommunicates with the interior of a horizontal crownpipe t) integraltherewith and with other tubular parts of said boiler-section,hereinafter referred to,and said vertical tubc4 has a curved upperend,as shown, which terminates at one end of said crown-pipe and, likethe tube 3, communicates with the interior thereof. Three tubularbranches 10, 12, and 13, constituting elements of said boiler-section A,are arranged one back of the other relative to a central vertical liney2 through the boiler, as illustrated in Fig. 1, said branches extendingfrom the side of said tube 3 in curved or quarter-turn lines andterminating at the under side of and communicating with the interior ofsaid crown-pipe 9. Said branches are also integral wlth the said tube 3and crownpipe and occupy positions over the grate 14, and are thusdirectly exposed to the hcatof a tire built thereon. Said sections A areso constructed and arranged side by side, as shown iu Fig. 2, on theopposite sides of the tire-box within the boiler as to leave opendraft-spaces :1: between the ripper parts of the sections, and thelatterhave cast upon their adjoining sides below said draft-openings .ocprojecting lips fr, whose edges are brought into engagement when thesections are in place side byside,thus closing up any opening betweenthe adjoining sections from thelowerend of said l raf t-spaces to apoint a little above the grate 14, and there the said closing lip 'utakes a somewhat different direction, as shown, and terminates under thegrate, and from the latter-named point the lip t 'extendsdownward tothelower end of the pipe 3, so that when the sections are grouped sideby side, as shown in Fig. 2, a close wall will be thereby formed on theopposite sides of the ash-pit. From the upper side of the grate aperforated lip w extends in a like manner from the side of the tube 3,and its upper end terminates at the lower end of that portion of the lip/U which terminates.

near the duct 7. By means of the form given to the lip lv between theduct Gand 7 an airbox ly is formed when two sections A are broughttogether between said sections through which air may flow from theash-pit B to a point over the tire on the grate, said air passingthrough the perforations 0 in saidlip tu, this latter-named perforatedlip, together with the adjoining flat side of the tube next tothe grate,serving as a part of the side wall of the 'ircbox. The said provisionfor the circulation of air from the ashpit B through the box y and theperforations o to mingle with the products of combustion in the fire-boxaffords means for supplying the tire with oxygen, whereby the fuel isconsumed under the most advantageous conditions. It will be understoodthat by means of the abovedescribed construction one of said air-boxes"ll/ is formed between thcV sides of adjoining sections.

The opposite sides of each of the ducts G of the section A are providedwith a horizontally-extending lip n, having acurved central notch e twoof which form the draft-opening K, (see Fig. 3,) and whose outer edge isin a plane at one end with the edge of said 11p e and its opposite endis in a plane with the edge of a Vertical lip m, extending from the sideof said tube 4 to the same extent that said lip lv extends from the sideof the tube 3, said lip m, however, extending from the lower end of saidtube 4 along its side to the crownpipe 9, and along the side of thelatter to its extremity, as shown in Fig. 5, to the end that when thesections .A are brought side to side, as in Figs. 1 and 3, the edges ofsaid lips m, r, and yn shall closely abut, thereby compellingtheproducts of combustion from the fire to pass in the direction indicatedby the arrow c at the top of the sections, through the openings a', andthence downward past the ducts S 7 (3, through the draft-opening K,tothe main draft-flue 71. on opposite sides of the ash-pit B. The saidmain draft or smoke tlue h, of which there are two,one on each side ofthe ash-pit under the grate 14,is formed within that part of the severalboiler-sections A surrounded by the lower ends of the tubes 3 and 4 andthe ducts 5 and (3, and consequently when the several sections A, whichcomprise the sides of the boiler, are united together, as shown in Figs.2 and 3, there is thereby formed saidsmoke-fluehatthelowerendsofandwithin the above-referred to parts of thesections A, such flue being thereby constructed on each side of theboiler and being continuous from the front to the rear side thereof, asclearly indicated in Fig. 3. In this last-named figure, and also in Fig.1, the dotted lines z indicate the position of the brick-work, withinwhich when the boiler is set the same is inclosed in the usual manner,and in Fig. 3 the dotted lines i indicate the position of a chimney, andthe lines i2 the direction of dues that in practice extend from the rearends of the tiues 71, in the lower ends of the sections A to thechimney. Itis thus seen that by means of such flue connection with achimney a direct draft from each flue h is provided, whereby theproducts of combustion are compelled to move from the tire-box upwardamong the branch tubes 1b, 12, and 13 of the several sections A of theboiler, thence through the passages x between said sections, and thencedownward between the walls of a chamber consisting of the verticaltubes. 3 and 4 of said sections,

past the ducts 6, 7, and S, and thence throughr the openings K (sec Fig.into said smoketlue h, and thence to the chimney, as aforesaid. lt willbe seen also by reference to Figs. 1, 3, and 5 that the side walls ofthe ash-pit B consist of the united lower ends of the said tubes 3 ofthe sections A, and therefore the heat existing in the ash-pit actsdirectly .against said walls to impart heat thereto and IOC IOS

IIO

to the water contained in those portions of` lirst and most directlyagainst the surfaces of the said branch pipes 10, 12, and 13, which aredirectly over the grate, and in which the water contained in the boileris found at its highest temperature, and thence downward, as abovedescribed, to the fines h, giving off the heat to the surfaces of theboiler-sections as it passes along. By this means it is clearly seenthat the heat'generated in the lire-box acts continuously and onlyagainst the surfaces of the boiler-sections which contain the water tobe heated from the time it escapes from the [ire-box until it reachesthe auxiliary flue above referred to between the boilerand the chimney,and by this means the entire efficiency of the products of combustion isutilized for heating purposes, it being well understood that a boilerconnected with a hotwater heating system receives the return-currentfrom the radiators at its lowerrnost point, and consequently the water1n the boiler which surrounds those portions of the boiler-- sectionswhich constitute the walls of the smoke-fines 7L is found to be of alower temperature than that of the products ofcombustion, which aredelivered into said fines from the lire-box, and hence the watersurrounding said fines has its temperature raised more or less afterreaching said lowest point in the boiler. Furthermore, the radiant heatfrom the ash-pit against the side walls thereof, as aforesaid, alsocontributes to the raising of the temperature of the water in the lowerflue-containing ends of the said'boilersections A.

The above-described advantages pertaining` to the construction of thelower draft-fines 7L within the sections of the boiler are wholly lostwhen such I'lues are constructed of brickwork, as heretofore practiced,beneath and upon which the lower ends of the boiler-sections rest. Thesaid boiler-sections A have their upper ends connected to the oppositesides of a flow-drum D-that is to say, the drum toward and into whichthe water heated in the boiler-sections liows and from which said heatedwater flows or passes off through an opening J in the rear of the drumor a similar opening or openings J2 in the upper side of said drum. Asuitable conducting-pipe is connected thereto leading to theheating-pipes or radiators. Connection between said sections Apand thedrum D is made by means of an elbow 15, preferably cast on the crownpipe9, and a short connection-pipe 1G, connected by one end with said elbowand its opposite end screwed into a socket 18 on the side of said drum,a packing-nut 17 being` placed on said pipe 16 and screwing against theface of the socket 18 to lock and pack the joint between said pipe andthe drum, any suitable packing being interposed therebetween, ifdesired.

A return-drum E is located at thc lower oud of the boiler and at thevlowest point thereof and in axial alignment with the flowdrum D andextends under the ash-pit B from the front to the rear side of theboiler, as shown in Figs. 23 and 5, and the lower ends of theboiler-sections A are connected to said return-drum by means of a pipe19 for each section, suitably connected by one end thereto and havingits opposite end connected to the drum E in substantially the samemanner as is one end of said pipe 16 connected to the drum D, a similarpacking-nut 2O being employed, preferably, at the drum-connected end ofsaid pipe 19. The return-pipe from the heating pipes and radiators isconnected t0 the rear end of said drum E at the opening f (see Fig. 2)or other suitable point thereon. An ash-pit floor of iron covers thedrum E and connecting-pipes 19.

The above-described arrangement of the drums D and E in axial alignmentone above the other and centrally between the sections A, together withthe long pipe connections 19 between the lower ends of said sections andthe drum E, permits the vertical expansion of the sections wit-houtinjury to the joints of the sections and connecting-pipes; A hollowtubular section C, constituting a movable bridge-wall, (see Figs. 1 and4,) is constructed and adapted to be located at the rear side of thetire-box, as shown, andis connected by its upper and lower ends to anintermediate connection-pipe 21 between the drums D and E at l) and b2thereon by suitable connectin g-pipes,which con n ecting-pipes may belonger or shorter, according to the length of the grate-bars which it isdesired to employ, whereby said section C may be correspondinglyadjusted relative to the rear end of said bars. By this means the watercontained in said section C becomes heated by its exposure to the fireand flows off atb into the` pipe 21, and through thelatter into the drumD, the return-current passing from the drum E into the pipe 2l at b2,and flowing from thence into the lower end of said section C, the lowerend of which constitutes the rear wall of the ashpit and its upper endthe rear wall of the reboX. A rib or lip p (shown in dotted lines inFig. 4t) is formed on the front side of the said wall C, directlyopposite the rear ends of the grate-bars, to prevent coal from droppingtherebetween. The spaces between the vertical tubes of the bridge-wallare closed by a web to prevent any rear draft therebetween.

Having fully described my invention, what I claim, and desire to secureby Letters Patent, is*- 1. A metallic boiler-section A, consisting ofthe integral combination of thev following members, forming one unit ofa sectional boiler, viz: the main vertical pipes 3 el, having horizontalcross-pipes 5, ti, 7, and S, the said pipes 3 and 4 uniting in acrown-pipe 9, and the curved pipes 10 12 13, whereby is formed therequisite intcrconn ectin g internal IOO IIO

water-passages, and, in a group of said sections, the external verticaland horizontal ilues to receive and conduct the products of combustionover the entire surface thereof `before their exit to a chimney,substantially as set forth.

2. A sectional boiler consisting of a number of hollow metallic sectionsarranged in two independent groups on opposite sides of the tire-box,each of said groups having therein at the lower end thereof below thetire-grate an independent horizontal smokeiiue communicating with thechimney and receiving the products of combustion through openings in itsupper side, the surrounding walls of which flue are composed of groupedportions of said hollow sections, substantially as set forth.

3. A sectional boiler consisting of a number of hollow metallic sectionsarranged vertically side by side in two independent groups on oppositesides of the tire-box, each of said groups having therein at the lowerend thereof below the lire-grate an independent horizontal smoke-fluecommunicating with a chimney and receiving the products of combustionthrough openings in its upper side, the surrounding walls of which flueare composed of grouped portions of said hollow sections, substantiallyas set forth.

4. A sectional boiler consisting of a number of hollow metallic sectionsarranged in two groups on opposite sides of the tire-box, each of saidgroups havingtherein at the lower end thereof below th eiire-grateahorizontal smoke- 3 iluccommunieatingwithachimneyandreceiving theproducts of combustion,thesurrounding walls of which are composed ofgrouped portions of said hollowseetions, combined with a hollowbridge-wall arranged vertically at the rear ot' the ashpit and tire-box,and a flow and a return drum, with which said sections are connected,substantiallyas set forth.

5. In a sectional boiler, a receiving and a discharge drum, one abovethe other in axial 4 alignment, to which said sections are connected,combined with a vertical hollow bridge-wall section located at the rearof the grate-bars, having water-circulating connections with said drums,substantially as set forth.

6. Ina sectional boiler, a receiving and a discharge drum, one above theother in axial alignment, to which said sections are connected, Combinedwith a vertical hollow 5 bridge-wall section located at the rear of thegrate-bars, having variable water-circulating connections with saiddrums, whereby the bridge-wall section may be set at different distancesfrom the front side of the fire-box, substantially as set forth.

JOHN Il. MILLS.

Witnesses:

H. A. CHAPIN, G. M. CHAMBERLAIN.

